Subscribe: Neuropsychology - Vol 24, Iss 1
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Neuropsychology focuses on (a) basic research, (b) the integration of basic and applied research, and (c) improved practice in the field of neuropsychology. The primary function of Neuropsychology is to publish original, empirical research on the relation

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Copyright: Copyright 2017 American Psychological Association

Long-term brain-injury-specific effects following preschool mild TBI: A study of theory of mind.


Objective: A previous study conducted by our group found theory of mind (ToM) differences in preschool children who sustained mild traumatic brain injury (mTBI) compared with typically developing peers, 6 months postinjury. The goals of the current longitudinal study were to determine whether these findings are the result of a brain-injury-specific effect or rather a general-injury effect, to examine the long-term evolution of ToM skills following preschool mTBI, as well as to investigate the links between ToM abilities and general social functioning. Method: Seventy-two children who sustained mTBI between the ages of 18 and 60 months were evaluated 6 and 18 months postinjury on ToM tasks including desires and emotions reasoning and false belief understanding. They were compared with 58 participants who sustained an orthopedic injury (OI) and 83 typically developing children (TDC). Results: The 3 groups did not differ on demographic and baseline characteristics. The mTBI group obtained poorer scores relative to both comparison groups on the desires and emotions reasoning task, both at 6 and 18 months injury. No correlations were found between injury characteristics and ToM performance. For the mTBI group, associations were found between ToM performance and global social competence. Conclusion: These findings suggest a brain-injury-specific effect that persists in the long-term following mTBI in preschool children. (PsycINFO Database Record (c) 2017 APA, all rights reserved)(image)

The impact of phenylalanine levels on cognitive outcomes in adults with phenylketonuria: Effects across tasks and developmental stages.


Objective: Phenylketonuria (PKU) is due to an inability to metabolize the amino acid phenylalanine (Phe), leading to its accumulation in the brain. Phe levels can be controlled following a protein-free diet, but cognitive impairments are still present. A number of questions remain to be answered related to which type of metabolic control is important, the age when it is important, the cognitive functions which are most affected and, the best tests to use to monitor cognitive health. Method: We investigated the impact of metabolic control at different ages on cognitive performance in 37 early treated adults with PKU. Results: (a) Phe variation was as associated to performance as average Phe showing that stable dietary control is as important as strict control; (b) For some tasks, current and adult Phe were stronger predictors of performance than childhood or adolescent Phe, showing the importance of a strict diet even in adulthood; and (c) The relationship between performance and Phe levels varied depending on time and cognitive domain. For some functions (sustained attention, visuomotor coordination), Phe at the time of testing was the best predictor. While for other functions (visual attention, executive functions) there was a diminishing or stable relationship across time. Conclusion: Results show the importance of selecting the right tasks to monitor outcomes across ages, but also that the impact of bio-chemical disruptions is different for different functions, at different ages. We show how inherited metabolic diseases offer us a unique vantage point to inform our understanding of brain development and functioning. (PsycINFO Database Record (c) 2017 APA, all rights reserved)(image)

Cognitive outcomes in early-treated adults with phenylketonuria (PKU): A comprehensive picture across domains.


Objective: Phenylketonuria (PKU) is an inherited metabolic disease which affects cognitive functions due to an inability to metabolize phenylalanine which leads to the accumulation of toxic by-products (Phe) in the brain. PKU can be effectively treated with a low phenylalanine diet, but some cognitive deficits remain. Studies have reported impairments, especially for processing speed and executive functions, but there is a lack of comprehensive assessment across cognitive domains. Moreover, it is important to establish outcomes in early treated adults with PKU (AwPKU) who have better metabolic control than groups previously reported in the literature. Method: We tested 37 AwPKU with an unprecedented number of tasks (N = 28) and measures (N = 44) and compared results with 30 controls matched for age and education. Results: We found (a) group impairments, particularly in tasks tapping speed of processing and complex executive functions; (b) high variability across participants, with a sizable number of AwPKU with completely normal performance (about 38%); (c) but also a sizable number of participants who were clearly impaired (about 24%); and (d) good performance in tasks tapping verbal learning, verbal memory and orthographic processing, indicating no generalized learning impairment. Conclusion: Our results indicate good outcomes, but also that deficits are still present with current treatment policies. (PsycINFO Database Record (c) 2017 APA, all rights reserved)(image)

Contralateral interictal and ictal EEG epileptiform activity accentuate memory impairment in unilateral mesial temporal sclerosis patients.


Objective: Memory impairment is a recognized complication of mesial temporal sclerosis (MTS). Epileptiform activity may negatively impact on cognition. We evaluated the impact of contralateral EEG involvement on memory in unilateral MTS (uMTS) patients. Method: Retrospective review of 121 right-handed uMTS patients (69 left) evaluated with prolonged video-EEG and verbal and nonverbal memory tests (Rey Auditory Verbal Learning Test and Rey-Osterrieth Complex figure), with additional very delayed trials. Patients were classified according to ictal/interictal EEG findings and MTS side as left or right concordant or discordant. Thirty-nine normal individuals who underwent the same neuropsychological battery served as controls. Results: Demographic, disease, and treatment features did not differ among groups. On the 7-day verbal memory free recall, left discordant performed significantly worse than controls and right concordant, recognized fewer words, and had more recognition errors than all other groups, including left concordant. For nonverbal memory, right discordant performed significantly worse than controls on delayed recall, and attained lower scores than other groups on immediate and 7-day recall, but this difference did not reach statistical significance. Left discordant had higher scores of memory complaints than controls and disclosed a trend toward accentuated memory impairment compared with the other groups over time. Conclusions: Our results suggest that contralateral electrographic involvement in uMTS was associated with more pronounced memory impairment for verbal material in left discordant patients, and to a lesser extent, for nonverbal material in right discordant patients. Left discordant group also had increased memory complaints. (PsycINFO Database Record (c) 2017 APA, all rights reserved)(image)

N400 effects of semantic richness can be modulated by task demands.


Semantic richness is a multidimensional construct that can be defined as the amount of semantic information associated with a concept. Objective: To investigate neurophysiological correlates of semantic richness information associated with words and its interaction with task demands. Method: Two different dimensions of semantic richness (number of associates and number of semantic neighbors) were investigated using event-related potentials (ERPs) in lexical decision (LDT) and semantic categorization tasks (SCT) using the same stimuli in 2 groups of participants (24 in each group). Results: The amplitude of the N400 ERP component, which is associated with semantic processing, was smaller for words with a high number of associates (p = .003 at fronto-centro-parietal sites) or semantic neighbors (p < .03 at centro-parietal sites) than for words with a low number of associates or number of semantic neighbors, in the LDT but not the SCT. Conclusions: These results suggest that the effects of semantic richness vary with task demands and may be used in a top-down manner to accommodate the current context. (PsycINFO Database Record (c) 2017 APA, all rights reserved)(image)

Autosomal dominant cerebellar ataxia, deafness, and narcolepsy (ADCA-DN) associated with progressive cognitive and behavioral deterioration.


Objective: Autosomal dominant cerebellar ataxia with deafness and narcolepsy (ADCA-DN) is an emerging syndrome caused by mutations in the C-terminus end of the TS domain of the DNMT1 gene. ADCA-DN is also associated with sensorimotor polyneuropathy, extrapyramidal, and dysautonomic signs, as well as dementia. Little has been reported about the progressive cognitive impairment associated with ADCA-DN. Our objective is to provide a detailed characterization of the cognitive profile of ADCA-DN. Method: Three members of a kindred with ADCA-DN underwent comprehensive neuropsychological testing and neuroimaging. Results: At baseline, 2 individuals demonstrated cognitive profiles with executive difficulties in some areas consistent with frontal-system dysfunction behaviorally and on standardized testing. The third individual was further in the disease course and exhibited more globally impaired cognition consistent with a diagnosis of dementia. Conclusions: This family demonstrated progressive neurodegeneration beginning with isolated areas of executive dysfunction and leading to globally impaired cognition and dementia. Cognitive decline occurred in parallel with neurological deterioration. The cognitive profile is similar to case reports of other individuals with an allelic neurological phenotype, Hereditary Sensory Autonomic Neuropathy 1E, also caused by DNMT1 mutations. (PsycINFO Database Record (c) 2017 APA, all rights reserved)(image)

Multimodal emotion processing deficits are present in amyotrophic lateral sclerosis.


Objective: Emotion processing abilities might be reduced in amyotrophic lateral sclerosis (ALS). Previous studies of emotion processing in ALS have inconsistent results, and are limited by variations in task difficulty, modalities examined, and participants’ cognitive status. The current study used a battery of emotion processing tasks at differing levels of difficulty and across different modalities (facial affect and voice prosody) to assess the extent of emotion processing deficits in nondemented ALS. Method: 33 ALS participants with intact basic cognition and 22 healthy controls completed the abbreviated Comprehensive Affect Testing System (CATS), which assesses simple and complex facial affect recognition, affective prosody recognition, cross-modal face-prosody integration, and semantic comprehension of affect. Participants also completed measures of executive function, mood, and functional impairment. Results: ALS participants showed impairments on complex facial affect recognition, affective prosody recognition, and cross-modal integration. In contrast, simple facial affect recognition and semantic comprehension of affect were intact. ALS participants did not have significant mood symptoms, and neither mood nor functional impairment was related to emotion processing. Performance on the cross-modal composite was related to executive function, however, this relationship was not apparent for facial or prosody recognition within a single modality. Conclusions: These results indicate that people living with ALS without dementia often have subtle difficulties with recognizing emotions in both faces and voices, even in the context of intact basic cognition. Clinicians should be aware of the potential for these emotion processing difficulties to be present in ALS and to affect interpersonal behavior and quality of life. (PsycINFO Database Record (c) 2017 APA, all rights reserved)(image)

The relationship between premorbid IQ and neurocognitive functioning in individuals with cocaine use disorders.


Objective: To determine whether premorbid IQ mediates performance on neurocognitive tests in individuals diagnosed with cocaine use disorder (CUD). Method: Recently abstinent cocaine users (N = 113) completed measures sensitive to the effects of cocaine on cognition: Conners’ Continuous Performance Task–II (CPT–II), n-back working memory test, and Hopkins Verbal Learning Task–Revised (HVLT–R). Premorbid IQ was calculated using the Oklahoma Premorbid Intelligence Estimate, which integrates scores from the Wechsler Adult Intelligence Scale–III and demographic variables. Participants were grouped according to their premorbid IQ using commonly accepted classifications of ability level (above average [>110], average [90–109], and below average [<90]) and comparisons in neurocognitive performance were performed using one-way analysis of variance. Results: Significant differences were detected between groups on the HVLT–R including Trial 1 (p = .002), total word recall across the 3 list-learning trials (p < .001), and recall following a delay (p < .001). Significant differences were also detected on the N-back, including auditory and visual accuracy (p = .022 and p < .001, respectively) and mean and maximum block length (p < .001). Although significant differences were observed between the above average and average groups (mean effect size = .418 [Cohen’s d]), the magnitude of group differences was greatest between the average and below average groups (mean effect size = .716). Conclusions: These results raise questions as to whether the neurocognitive impairment observed in individuals diagnosed with CUD predated the onset of cocaine use or whether the impairments were caused by cocaine use. Because these impairments are potential risk factors for poor treatment outcomes, it is important to consider the need to modify treatment programs to account for lower premorbid IQ. (PsycINFO Database Record (c) 2017 APA, all rights reserved)(image)

Estradiol-related variations in top-down and bottom-up processes of cerebral lateralization.


Objective: Natural fluctuations of sex hormones have been shown to modulate cerebral lateralization in dichotic listening tasks. Two recent studies presented contradictory notions regarding the mechanism of this effect. Specifically, whereas Hjelmervik et al. (2012) suggested that estradiol affects lateralization by enhancing top-down processes, such as cognitive control, Hodgetts, Weis, and Hausmann, (2015) suggested that the effect was attributable to estradiol-related variations in bottom-up aspects of lateralization. Method: The present study used 2 well-established left- and right-lateralized dichotic listening tasks (Grimshaw, Kwasny, Covell, & John, 2003; Grimshaw, Séguin, & Godfrey, 2009; Hugdahl, 1995, 2003), with forced-attention conditions to differentiate between these 2 ideas. Fifty-two naturally cycling women underwent both tasks, during either the menstrual, follicular, or luteal cycle phase. Saliva estradiol and progesterone levels were determined by luminescence immunoassays. Results: The results showed that sex hormones did not affect language lateralization, which may be attributable to the larger degree of lateralization yielded by the task, compared with that shown by Hodgetts et al. (2015). In the emotional prosody task, high levels of estradiol were marginally associated with a reduction in cognitive control, whereas the language task yielded no cycle effects for either top-down or bottom-up processes. Conclusions: In sum, the current study revealed weak support for the idea that estradiol affects top-down control of lateralization, as measured with dichotic listening tasks. Given that the task employed in the present study seemed less cognitively demanding than that used previously, it is suggested that estradiol-related inter- and intraindividual variations in lateralization are small when task demands are low. (PsycINFO Database Record (c) 2017 APA, all rights reserved)(image)

Beyond binary: Exploring the merits of three depression groups in multiple sclerosis.


Objective: Depression has been traditionally explored in the context of multiple sclerosis (MS) as a binary construct (depressed, not depressed). However, given the 50% lifetime prevalence rate of depression in MS, it may be useful to consider not only currently depressed versus nondepressed patients, but to evaluate groups that better characterize the complexity of MS depression. The objective of the current study was to examine demographic, cognitive, illness, and psychosocial variables thought to associate with depression in MS across 3 groups: currently depressed, remitted depression, and never been depressed. Method: Fifty-four individuals with MS were examined. Current depression status was measured using the Beck Depression Inventory—Fast Screen (BDI-FS; Beck, Steer, & Brown, 2000). Past depression was evaluated using the Structured Clinical Interview for DSM–IV Disorders (SCID-IV; First, Spitzer, Gibbon, & Williams, 1998) and a semistructured psychosocial interview. Results: The results of the current study show that evaluating depression in 3 groups is useful for exploring risk, protective, and compensatory factors of depression in MS. A consistent grouping pattern (e.g., the remitted depression group always functioning the same as the never been depressed group) was not found among the variables examined; rather, several different patterns were observed. Several of these patterns revealed differences between the remitted depression and never been depressed groups; these differences would not have been observed had these 2 groups been combined into a “not currently depressed” group. Conclusions: These different patterns yield important information about the complex relationships of depression in MS that may be obscured when depression is viewed as a binary construct. (PsycINFO Database Record (c) 2017 APA, all rights reserved)(image)

Episodic future thinking following vmPFC damage: Impaired event construction, maintenance, or narration?


Objective: Functional neuroimaging and lesion studies show that the ventromedial prefrontal cortex (vmPFC) is implicated in episodic future thinking (EFT), yet its role remains unclear. In this study, we sought to (a) confirm recent findings of impaired EFT in patients with lesions to the vmPFC (vmPFC patients) using a new task, and (b) investigate the influence of nonepisodic mechanisms, namely, narrative construction and working memory maintenance, on vmPFC patients’ EFT performance. Method: vmPFC patients and healthy participants imagined future events using pictures as cues, described pictures, or described pictures while maintaining them in working memory after an observation phase. Results: Compared with the controls, vmPFC patients produced less specific reports across all conditions, as indicated by fewer internal (episodic) but a similar number of external (semantic) details. However, controlling for description and working memory performance did not eliminate group differences in EFT. Moreover, vmPFC damage reduced the proportion of internal-to-total details for EFT only. Conclusions: These results indicate that EFT problems in vmPFC patients are not merely the reflection of problems in maintaining in working memory and narrating events, but, more likely, of an impairment upstream, in creating novel events. (PsycINFO Database Record (c) 2017 APA, all rights reserved)(image)